Computer system and method for assessing dynamic bone quality

ABSTRACT

A computer system for assessing dynamic bone quality is provided, including a memory that stores executable instructions, a central processing unit (CPU) capable of accessing the memory and executing the instructions to provide an output, and a receiver for receiving data input and transmitting it to the CPU, wherein the receiver is operably connected to: (1) a plurality of accelerometers, each accelerometer adapted to contact an exterior surface of a human subject at a load-bearing anatomical site and to receive input from each point of contact including acceleration response data; and (2) a force plate adapted to receive input including vertical ground reaction force data provided by a heel strike on the force plate, wherein the CPU executes the instructions to process the input data transmitted from the receiver to provide the output as a bone damping value. A method for assessing dynamic bone quality is also provided.

RELATED APPLICATION

This application claims priority to U.S. Provisional Patent ApplicationNo. 61/035,884, filed Mar. 12, 2008, which application is herebyincorporated by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates to the field of bone screening anddiagnosis. Specifically, the invention relates to a computer system andmethod for assessing dynamic bone quality in a human subject bymeasuring the bone shock absorption properties of the bone underrealistic, in vivo loading conditions.

BACKGROUND OF THE INVENTION

Osteoporosis has a significant impact on the population of the UnitedStates, with more than 10 million people affected by the disease and 24million at risk. Osteoporosis is associated with decreased bone mass anddeterioration of the trabecular architecture of the bone, whichcollectively impact the bone's mechanical properties. Often, thisdegenerative disease leads to bone fracture (2 million per year), withassociated costs exceeding $16 billion annually. Traditionally,measurement of bone mineral density (BMD) has been the predominantdiagnostic and screening tool for osteoporosis and other degenerativebone diseases.

Dual energy x-ray absorptiometry, or DXA, is the most popular currentmethod of assessing bone density. In this method, a subject is exposedto low-dose x-rays having two distinct energy peaks, with differentcharacteristics in soft tissue and bone. Subtraction of the soft tissueabsorption allows quantification of BMD. The procedure is carried outwhile the subject is at rest, thus providing BMD data for the bone understatic conditions.

However, structural failure of the human bone rarely occurs under staticconditions. A better understanding of bone fracture and preventionrequires measurement of the biomechanical properties of the bone whenexposed to realistic, in vivo loading—that is, an assessment of“dynamic” bone quality.

The transmission, absorption and attenuation of energy that intakes tothe skeleton due to heel strike is an important component of bonephysiology and pathology. The human locomotion system, which consists ofnatural shock absorbers (joints with viscoelastic components, articularcartilage, meniscus, intervertebral disks, trabecular bone, etc.), issubjected to constant loading and impact not only during weight liftingactivities but also during normal daily activities such as walking,running, stair-climbing, etc. During heel strike, the vertical forcecomponent acting on the foot is on the order of 1.5 times the bodyweight depending upon walking velocity. These force waves are graduallyattenuated by the body's natural shock absorbers on their way toward thehead. The process of force wave attenuation is the body's natural way ofprotecting the most vital organ, the brain.

Among all natural shock absorbers in the human body, the trabecular bonehas the highest capacity (170 times higher than that of cartilage) toattenuate incoming shock waves associated with heel-strike duringwalking and running. Since osteoporosis is associated with decreasedbone mass and deterioration of trabecular architecture of the bone, thedisease detrimentally changes the bone's natural shock absorbingcapacity. The need exists to develop non-invasive, economical tools forassessing and monitoring dynamic bone quality.

The present invention is directed to a computer system and method forquantifying bone shock absorption (BSA) under dynamic conditions inorder to assess the dynamic bone quality in a subject. The BSA variable,bone damping (ζ), is a sensitive measure of the bone's structuralintegrity, a useful diagnostic of osteoporosis, and a valuable indicatorof fracture risk.

SUMMARY OF THE INVENTION

Bone shock absorption (BSA), as expressed in the measurement of bonedamping, is a useful tool in diagnosing osteoporosis and assessingdynamic bone quality.

Accordingly, it is an object of the present invention to provide acomputer system for assessing dynamic bone quality, the systemcomprising:

a memory that stores executable instructions;

a central processing unit (CPU) capable of accessing the memory andexecuting the instructions to provide an output; and a receiver forreceiving data input and transmitting it to the CPU;

wherein the receiver is operably connected to:

(1) a plurality of accelerometers, each accelerometer adapted to contactan exterior surface of a human subject at a load-bearing anatomical siteof the subject and to receive input from each point of contactcomprising acceleration response data; and (2) a force plate adapted toreceive input comprising vertical ground reaction force data provided bya heel strike on the force plate;

wherein the CPU executes the instructions to process the input datatransmitted from the receiver to provide the output as a bone dampingvalue.

It is a further object of the present invention to provide a method forassessing dynamic bone quality in a human subject, the method comprisingthe steps of:

(a) contacting at least one accelerometer to an exterior surface of ahuman subject at a load-bearing anatomical site of the subject;

(b) directing the subject to strike a heel on a force plate;

(c) measuring vertical ground reaction force due to the heel strike;

(d) measuring an acceleration response at each of the accelerometers;

(e) processing the vertical ground reaction force and accelerationresponses at a CPU to determine a bone damping value; and

(f) comparing the bone damping value to a reference value to assessdynamic bone quality in the human subject.

These and other objects, features, and advantages will become apparentto those of ordinary skill in the art from a reading of the followingdetailed description and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1. Damping values above and below fracture site for fracture andnon-fracture subjects with osteoporosis. Absolute damping value of thefracture group was significantly lower than that of the non-fracturegroup for the lower back (p=0.003) and upper back (p=0.009) regions.

FIG. 2. Damping value data of right femoral condyle for five testgroups: healthy adults, healthy youth, individuals with osteoporosis andwithout fracture, individuals with osteoarthritis, and individuals withosteoporosis and with fracture. Damping values are significantlydifferent for all comparisons (p values ranging between 0.04 and0.0001), except between healthy adults and healthy youth and individualswith osteoporosis without fracture and individuals with osteoarthritis.

FIG. 3. An embodiment of a computer system of the present invention.

FIG. 4. An embodiment of a computer system of the present invention.

FIG. 5. Representation of acceleration response data in the frequencydomain from an accelerometer.

FIG. 6. Example of vertical ground reaction force data generated by aheel strike on a force plate.

FIG. 7. Example of acceleration response data generated at aload-bearing anatomical site, in response to a heel strike.

DETAILED DESCRIPTION OF THE INVENTION

The following is a list of definitions for terms used herein.

The term “dynamic bone quality,” as used herein, refers to the boneshock absorption properties of the bone when exposed to in vivo loading.Dynamic bone quality can be assessed by measuring the damping propertiesof load-bearing bones and expressed as a bone damping value.

The term “damping,” as used herein, refers to the ability of anystructure to reduce the amplitude of oscillations in an oscillatorysystem, thus absorbing an applied shock wave. “Bone damping,” as usedherein, refers to the ability of a bone to absorb an applied shock wave.In the context of the human musculoskeletal structure, such a shock wavemay be produced, for example, by a heel strike. However, one skilled inthe art will appreciate that bone damping occurs and can be measured inresponse to any shock applied to the musculoskeletal structure of thebody.

The term “memory,” as used herein, refers to integrated circuits thatstore information in electronic devices and includes both volatile andnon-volatile memory.

The term “executable instructions,” as used herein, refers tomachine-executable instructions that are carried out by a centralprocessing unit, or CPU, which accesses the memory in a computer system.

The term “central processing unit,” or “CPU,” as used herein, refers toan electronic circuit capable of accessing memory and executing computerprograms stored therein.

The term “output,” as used herein, refers to the result of dataprocessing by a CPU. In one embodiment of the invention, the output is abone damping value. In another embodiment, output can include dB down inthe Fast Fourier Transform (FFT) responses at each load-bearinganatomical site; numbers of peaks in the FFT responses at eachload-bearing anatomical site; area under the FFT response graphs at eachload-bearing anatomical site; and resonance frequency from FFT responsegraphs at each load-bearing anatomical site. See Ewing, D. J., ModalTesting: Theory and Practice, Research Studies Press Ltd., John Wileyand Sons, Inc. (1984). Output can be provided in a variety of ways,including, but not limited to, display on a computer screen or in aprinted report.

The term “receiver,” as used herein, refers to any device suitable forreceiving acceleration response data from the accelerometers and groundreaction force data from the force plate and transmitting the same tothe CPU.

The term “accelerometer,” as used herein, refers to a sensor capable ofmeasuring the rate of change in velocity of the object being tested. Inone embodiment of the invention, a plurality of accelerometers isemployed, each of which is operably connected to the receiver. Suitableaccelerometers include, but are not limited to, wired accelerometers,wireless MEMS based nano-accelerometers, and combinations thereof.

The term “load-bearing anatomical site,” as used herein, refers toanatomical sites that support body segment weights situated immediatelyabove the site of interest. For example, the feet support the weight ofthe entire body; the knees support the weight of the body above theknees, and so forth. Examples of load-bearing anatomical sites suitablefor use in the present invention include, but are not limited to, theshin, tibia, femur, and vertebrae. In one embodiment of the invention,accelerometers are contacted to exterior surfaces of the subject at thelower shin above the ankle, tibia, femur, third lumbar vertebra andseventh thoracic vertebra.

The term “non-load-bearing anatomical site,” as used herein, refers toan anatomical site that does not ordinarily support body weight. Forexample, the arms are generally non-load-bearing anatomical sites,unless a subject uses his arms to support body weight, such as in theevent of a fall where the subject uses his arms to brace the impact.Another example of a non-load-bearing anatomical site is the head, andmore particularly the forehead.

The term “acceleration response data,” as used herein, refers to themeasurement of raw acceleration versus time. Acceleration response datais produced by each accelerometer in response to an applied shock waveto the body, for example, after the subject completes a heel strike.

The term “force plate,” as used herein, refers to an apparatuscomprising sensors capable of measuring an applied force. Suitable forceplates are commercially available, for example, from Advanced MechanicalTechnology, Inc. (Watertown, Mass.). In a specific embodiment of theinvention, the force plate is capable of measuring vertical groundreaction force generated by a heel strike.

The term “vertical ground reaction force data,” as used herein, refersto a reaction force generated in response to an applied force.Consistent with Newton's Third Law, for every action there is an equaland opposite reaction. Thus, for example, when a subject strikes a forceplate with his or her heel, a ground reaction force is generated. Theforce plate can capture this ground reaction force in vertical,horizontal, and lateral directions. In one embodiment of the invention,the vertical ground reaction force is measured and the vertical groundreaction force data is used to determine a bone damping value.

The term “heel strike,” as used herein, refers to the act of striking asurface, such as a force plate, with the heel of the foot. For example,a subject can produce a heel strike by stepping or stomping on a forceplate.

The term “reference value,” as used herein, refers to an average bonedamping value obtained from normal, healthy subjects. In one embodiment,the reference value for bone damping is a range of from about 18 toabout 30. In another embodiment, the reference value is a range of fromabout 20 to about 27. In yet another embodiment, the reference value isa range of from about 22 to about 26. In yet another embodiment, thereference value for bone damping is about 24.

Computer System for Assessing Dynamic Bone Quality

In one embodiment of the invention, a computer system 1 for assessingdynamic bone quality is provided, the system comprising: a memory 2 thatstores executable instructions; a central processing unit (CPU) 4capable of accessing the memory and executing the instructions toprovide an output; and a receiver 6 for receiving data input andtransmitting it to the CPU 4; wherein the receiver 6 is operablyconnected to: (1) a plurality of accelerometers 8, each accelerometeradapted to contact an exterior surface of a human subject at aload-bearing anatomical site of the subject and to receive input fromeach point of contact comprising acceleration response data; and (2) aforce plate 12 adapted to receive input comprising vertical groundreaction force data provided by a heel strike on the force plate;wherein the CPU 4 executes the instructions to process the input datatransmitted from the receiver 6 to provide the output as a bone dampingvalue (see, for example, FIG. 3). Suitable load-bearing anatomical sitesinclude, but are not limited to, the tibias, the femurs, and thevertebrae.

In another embodiment of the invention, the receiver 6 is operablyconnected to at least one accelerometer 10 adapted to contact anexterior surface of the subject at a non-load-bearing anatomical site ofthe subject. Suitable non-load-bearing anatomical sites include, but arenot limited to, the head and forehead.

In one embodiment of the invention, the executable instructions compriseperforming algorithms on the acceleration response data and the verticalground reaction force data in order to determine a bone damping value,the algorithms selected from the group consisting Fast Fourier Transform(FFT), transfer function, and Frequency Response Function (FRF).

Many varieties of accelerometers are known in the art and suitable foruse in the present invention. Indeed, any accelerometer capable ofmeasuring acceleration response and transmitting acceleration responsedata from load-bearing and non-load-bearing anatomical sites may beused. In a specific embodiment, the accelerometers (located at eitherload-bearing or non-load-bearing anatomical sites) are selected from thegroup consisting of wired accelerometers, wireless accelerometers, MEMSbased nano-accelerometers, and combinations thereof. In a more specificembodiment, the accelerometers are wireless MEMS basednano-accelerometers (see, for example, FIG. 4, illustrating a wirelessembodiment of the computer system).

Method for Assessing Dynamic Bone Quality

In another embodiment of the invention, a method for assessing dynamicbone quality in a human subject is provided, the method comprising thesteps of:

-   -   (a) contacting at least one accelerometer to an exterior surface        of a human subject at a load-bearing anatomical site of the        subject;    -   (b) directing the subject to strike a heel on a force plate;    -   (c) measuring vertical ground reaction force due to the heel        strike;    -   (d) measuring an acceleration response at each of the        accelerometers;    -   (e) processing the vertical ground reaction force and        acceleration responses at a CPU to determine a bone damping        value; and    -   (f) comparing the bone damping value to a reference value to        assess dynamic bone quality in the human subject.

In another embodiment, step (a) further comprises contacting at leastone accelerometer to an exterior surface of a human subject at anon-load-bearing anatomical site of the subject, such as the forehead.

The bone damping value can be compared to a reference value,representing normal, healthy individuals, in order to assess dynamicbone quality. In one embodiment of the invention, a bone damping valuelower than the reference value indicates a presence or risk of bonedisease. In a specific embodiment, the bone disease is selected from thegroup consisting of osteoporosis, osteoarthritis, and bone fracture.

In another embodiment of the invention, the method further comprisesdetermining a bone mineral density, or BMD, of the human subject.Suitable methods for determining BMD are well-known in the art. See, forexample, “NIH Consensus Development Panel on Osteoporosis Prevention,Diagnosis, and Therapy,” Journal of the American Medical Association285: 785-95 (2001). In one embodiment, the BMD is determined by dualenergy x-ray absorptiometry (DXA).

Many types of accelerometers are known in the art and suitable for usein the present invention. Indeed, any accelerometer capable of measuringacceleration response and transmitting acceleration response data fromload-bearing and non-load-bearing anatomical sites may be used in themethod. In a specific embodiment, the accelerometers are selected fromthe group consisting of wired accelerometers, wireless accelerometers,MEMS based nano-accelerometers, and combinations thereof. In a morespecific embodiment, the accelerometers are wireless MEMS basednano-accelerometers.

In another embodiment of the invention, the processing step (e)comprises performing algorithms selected from the group consisting FastFourier Transform (FFT), transfer function, and Frequency ResponseFunction (FRF).

Calculation of Bone Damping Value

Data collected from the force plate and accelerometers after heel strikeare used to calculate the bone damping value for each anatomical site ofinterest. The force plate measures the time domain force profile createdby the heel strike (the vertical ground reaction force data). See, forexample, FIG. 6. Each accelerometer measures the time domainacceleration profiles caused by the heel strike (acceleration responsedata) at each anatomical site of interest. See, for example, FIG. 7. Thedata is transmitted to the computer system, programmed to determine thebone damping value at each anatomical site.

In order to determine bone damping, the musculoskeletal system istreated as a single degree of freedom system responding to the transientforce due to heel strike. A Fast Fourier Transform (FFT) of the verticalground reaction force data and the acceleration response data at allanatomical test sites is performed. The number of peaks in the frequencydomain up to 100 Hz are considered for the analysis. The first dominantfrequency and next four peaks in the increasing frequency direction arecomputed for acceleration waveforms at all anatomical sites. Thefrequency response function (FRF) of vertical ground reaction force andacceleration response are obtained using the following equation:

FRF=FFT of acceleration response at an anatomical site/FFT of verticalground reaction force.

Damping value is obtained directly from the measured FRF using thestructural bandwidth and resonance frequency method. See Ewing, D. J.,Modal Testing: Theory and Practice, Research Studies Press Ltd., JohnWiley and Sons, Inc. (1984) and Coleman, R E., Experimental structuraldynamics: An introduction to experimental methods of characterizingvibrating structures, Author House (2004). By this method, thestructural bandwidth is manifest in the FRF real part as the frequencyseparation between two extrema, symmetric about the resonance frequency,whereas the resonance frequency coincides with a single peak in the FRFimaginary part. The damping value is determined according to thefollowing equation:

Bone damping value ζ=(½)*(structural bandwidth/resonance frequency)

Using this equation, a bone damping value is determined for eachanatomical site of interest.

Additional Outputs

Other outputs are also optionally provided by the system, including dBdown in the Fast Fourier Transform (FFT) curves corresponding to eachload-bearing anatomical site; numbers of peaks in the FFT responses ateach load-bearing anatomical site; area under the FFT response graphs ateach load-bearing anatomical site; and resonance frequency from FFTresponse graphs at each load-bearing anatomical site.

dB down of an acceleration FFT curve is calculated according to thefollowing method:

dB1=20 log₁₀(A2/A1)

dB2=20 log₁₀(A3/A1)

wherein A1, A2, and A3 are obtained from the FFT curve, as represented,for example, in FIG. 5.

EXAMPLES

The following examples are given by way of illustration, and are in noway intended to limit the scope of the present invention.

Example 1

A Caucasian, post-menopausal female subject has accelerometers placed incontact with load-bearing anatomical sites on the exterior surface ofher body, the sites comprising the shin bones immediately above theankles, the tibias, the lateral femoral condyles, the third lumbarvertebra, and the seventh thoracic vertebra. An additional accelerometeris contacted to her forehead, a non-load-bearing anatomical site. Thesubject is then instructed to strike her heel on the force plate. Theforce plate measures the time domain force profile created by the heelstrike (the vertical ground reaction force data). Each accelerometermeasures the time domain acceleration profiles caused by the heel strike(acceleration response data) at each anatomical site of interest. Thedata is transmitted to the computer system, which is programmed todetermine the bone damping value at each anatomical site.

In order to determine bone damping, the musculoskeletal system istreated as a single degree of freedom system responding to the transientforce due to heel strike. A Fast Fourier Transform (FFT) of the verticalground reaction force data and the acceleration response data at allanatomical test sites is performed. The number of peaks in the frequencydomain up to 100 Hz are considered for the analysis. The first dominantfrequency and next four peaks in the increasing frequency direction arecomputed for acceleration waveforms at all anatomical sites. Thefrequency response function (FRF) of vertical ground reaction force andacceleration response are obtained using the following equation:

FRF=FFT of acceleration response at an anatomical site/FFT of verticalground reaction force.

Damping value is obtained directly from the measured FRF using thestructural bandwidth and resonance frequency method. By this method, thestructural bandwidth is manifest in the FRF real part as the frequencyseparation between two extrema, symmetric about the resonance frequency,whereas the resonance frequency coincides with a single peak in the FRFimaginary part. The damping value is determined according to thefollowing equation:

Bone damping value=(½*structural bandwidth)/resonance frequency

Using this equation, a bone damping value is determined for eachanatomical site of interest. The bone damping value of the femalesubject at the right femoral condyle is 5.0, significantly lower thanthe bone damping value of a normal healthy adult. The bone damping dataindicate the subject is suffering from osteoporosis and is at risk fordeveloping bone fracture.

Example 2

Decreased Bone Shock Absorbing Capacity in Individuals with Bone Disease

Five groups of subjects undergo dynamic bone quality analysis, thegroups including healthy adults (N=10), healthy youth (N=18),individuals with osteoporosis and without fracture (N=39), individualswith osteoarthritis (N=8), and individuals with osteoporosis and withfracture (N=28). Each individual has accelerometers placed in contactwith load-bearing anatomical sites on the exterior surface of the body,the sites comprising the shin bones immediately above the ankles, thetibias, the lateral femoral condyles, the third lumbar vertebra, and theseventh thoracic vertebra. An additional accelerometer is contacted tothe forehead of the test subjects, a non-load-bearing anatomical site.

Each individual is instructed to strike his or her heel on the forceplate. Bone damping values are determined for each subject,corresponding to each anatomical site of interest. The data indicate aprogressively decreasing trend in a continuum of data from healthy,young bone to stiffer bone in individuals having osteoarthritis, to evenmore stiff and brittle bone in individuals having osteoporosis. (SeeFIG. 2). Damping values are significantly different for all comparisons(p values ranging between 0.04 and 0.0001), except between healthyadults and healthy youth and individuals with osteoporosis withoutfracture and individuals with osteoarthritis. The data show thatindividuals with degenerative skeletal disorders have significantlydecreased bone shock absorbing capacity, as compared to normal healthysubjects.

Example 3 Damping Values at the Site of Fracture

The data from the two groups of Caucasian post-menopausal femalesubjects of Example 2 are further considered (osteoporosis withfracture, N=28 and osteoporosis without fracture, N=39) in order todemonstrate the differences in damping values between groups at the siteof fracture. The site of fracture was between the third lumbar vertebra(lower back) and the seventh thoracic vertebra (upper back). Theabsolute damping value of the fracture group was significantly lowerthan that of the non-fracture group for lower back (p=0.003) as well asfor the upper back regions (p=0.009) (see FIG. 1). The absolute dampingvalues for the fracture group due to heel-strike at the fracture sites(damping value at upper back: 1.26 and at lower back: 3.15) weresignificantly lower than that at tibia (damping value=5.3) and femoral(damping value=5.1) bone sites (data not shown). The results indicatethat osteoporosis has a more detrimental impact on damping properties ofthe bone at the fracture site as compared to non-fracture sites (seeFIGS. 1 and 2).

All documents cited are, in relevant part, incorporated herein byreference; the citation of any document is not to be construed as anadmission that it is prior art with respect to the present invention.

While particular embodiments of the present invention have beenillustrated and described, it would be obvious to those skilled in theart that various other changes and modifications can be made withoutdeparting from the spirit and scope of the invention. It is thereforeintended to cover in the appended claims all such changes andmodifications that are within the scope of this invention.

We claim:
 1. A computer system for assessing dynamic bone quality, thesystem comprising: a memory that stores executable instructions; acentral processing unit (CPU) capable of accessing the memory andexecuting the instructions to provide an output; and a receiver forreceiving data input and transmitting it to the CPU; wherein thereceiver is operably connected to: (1) a plurality of accelerometers,each accelerometer adapted to contact an exterior surface of a humansubject at a load-bearing anatomical site of the subject and to receiveinput from each point of contact comprising acceleration response data;and (2) a force plate adapted to receive input comprising verticalground reaction force data provided by a heel strike on the force plate;wherein the CPU executes the instructions to process the input datatransmitted from the receiver to provide the output as a bone dampingvalue.
 2. The computer system of claim 1, wherein the receiver isoperably connected to at least one accelerometer adapted to contact anexterior surface of the subject at a non-load-bearing anatomical site ofthe subject.
 3. The computer system of claim 1, wherein the load-bearinganatomical sites are selected from the group consisting of the shins,the tibias, the femurs, and the vertebrae.
 4. The computer system ofclaim 1, wherein the plurality of accelerometers is selected from thegroup consisting of wired accelerometers, wireless accelerometers, MEMSbased nano-accelerometers, and combinations thereof.
 5. The computersystem of claim 2 wherein the at least one accelerometer is selectedfrom the group consisting of wired accelerometers, wirelessaccelerometers, MEMS based nano-accelerometers, and combinationsthereof.
 6. The computer system of claim 1, wherein the executableinstructions comprise performing algorithms on the acceleration responsedata and the vertical ground reaction force data, the algorithmsselected from the group consisting Fast Fourier Transform (FFT),transfer function, and Frequency Response Function (FRF).
 7. A methodfor assessing dynamic bone quality in a human subject, the methodcomprising the steps of: (a) contacting at least one accelerometer to anexterior surface of a human subject at a load-bearing anatomical site ofthe subject; (b) directing the subject to strike a heel on a forceplate; (c) measuring vertical ground reaction force due to the heelstrike; (d) measuring an acceleration response at each of theaccelerometers; (e) processing the vertical ground reaction force andacceleration responses at a CPU to determine a bone damping value; and(f) comparing the bone damping value to a reference value to assessdynamic bone quality in the human subject.
 8. The method of claim 7,wherein step (a) further comprises contacting at least one accelerometerto an exterior surface of a human subject at a non-load-bearinganatomical site of the subject.
 9. The method of claim 7, wherein theload-bearing anatomical sites are selected from the group consisting ofthe shins, the tibias, the femurs, and the vertebrae.
 10. The method ofclaim 7 wherein the at least one accelerometer is selected from thegroup consisting of wired accelerometers, wireless accelerometers, MEMSbased nano-accelerometers, and combinations thereof.
 11. The method ofclaim 8 wherein the at least one accelerometer is selected from thegroup consisting of wired accelerometers, wireless accelerometers, MEMSbased nano-accelerometers, and combinations thereof.
 12. The method ofclaim 7 wherein the processing step (e) comprises performing algorithmsselected from the group consisting Fast Fourier Transform (FFT),transfer function, and Frequency Response Function (FRF).
 13. The methodof claim 7, wherein a bone damping value lower than the reference valueindicates a risk of bone disease.
 14. The method claim 13, wherein thebone disease is selected from the group consisting of osteoporosis,osteoarthritis, and bone fracture.
 15. The method of claim 7, furthercomprising determining a bone mineral density of the human subject. 16.The method of claim 15 wherein the bone mineral density is determined bydual energy x-ray absorptiometry (DXA).